This relates to testing, and more particularly, to wireless testing of electronic devices.
Electronic devices such as cellular telephones and portable computers contain wireless communications circuitry. A typical device contains an antenna coupled to a radio-frequency transceiver and an associated processor. During data transmission operations, the processor supplies data to the radio-frequency transceiver. A radio-frequency transmitter in the transceiver transmits the data using the antenna. During data reception operations, a receiver in the radio-frequency transceiver receives radio-frequency signals through the antenna and passes these signals to the processor.
Wireless electronic devices such as these are generally tested during manufacturing. When a wireless electronic device is being tested, the device is typically referred to as a device under test (DUT). The radio-frequency performance of a device under test may be tested using wired and wireless connections. With a typical wired test, a test probe is connected to a connector on a printed circuit board in the device. The connector may, for example, be interposed in a transmission line path between the transceiver and the antenna. The probe may tap into the transmission line to perform test measurements. For example, the test probe may be used to make measurements on the amount of power received through the antenna.
Wired tests such as these may be helpful in determining whether a device is functioning properly, but may not be sufficient in many situations. For example, wired measurements that bypass the antenna are not able to test for proper antenna functionality. Wireless measurements at a connector do not provide a direct measurement of the amount of radio-frequency signal power that is actually received at the input to the receiver, because the connector for the wired tap point is upstream from the receiver. Moreover, use of a cable to form a wired connection between a tester and a device under test introduces a conductive element into the test environment. Because the cable can influence the distribution of radio-frequency signals in the vicinity of the device under test, accurate wireless measurements can be difficult in the presence of the cable.
Wireless testing avoids some of these shortcomings of wired radio-frequency tests. With wireless testing, test equipment exchanges wireless signals with the device under test. The type of testing that is performed depends on the type of tester that is used. Low level tests (i.e., physical layer tests) can be performed using relatively simple equipment such as power meters. A power meter may, for example, be used to measure how much radio-frequency power is being transmitted by a device under test. Higher level tests (e.g., network layer tests) can be performed using complex test equipment such as call boxes. High level tests may, for example, involve the transmission and reception of protocol-compliant wireless test messages. These high level tests may be used to evaluate how well a device under test performs typical network layer tasks.
Although a variety of test equipment is available for performing wireless tests, there are gaps in test coverage. For example, existing wireless test techniques are not able to measure how much power is actually received at the radio-frequency receiver in the device under test.
Power meter equipment and other external test equipment is not able to measure received power levels in the device under test, because wired probes can only connect to the device under test at connector locations that bypass antennas and that are located upstream from the receiver and because wired test probes tend to disturb the wireless environment of the device.
Call boxes and other test equipment that handles network layer testing is typically only able to exchange predetermined protocol-compliant network messages with the device under test. For example, call boxes that handle code division multiple access (CDMA) protocols are only able to handle CDMA network messages that are compliant with CDMA protocols. These protocols do not include network message formats for transmitting receiver power measurements.
It would therefore be desirable to provide improved ways in which to make measurements on the amount of radio-frequency signal power that is received by the receiver in an electronic device.